BMW, Dinan S3 BMW 335i

BMW, Dinan S3 BMW 335i

The car you see here was no doubt envisioned by a legion of Internet dreamers—breathlessly commenting, “Crank up the boost!”—mere seconds after BMW debuted the twin-turbo 335i for 2007. But it took five Dinan employees hacking away at BMW’s software for a year and a half to finally make it happen.

It was worth the wait. Steve Dinan has sold more than 2000 software upgrades for the 135i/335i, making it the most popular upgrade in his company’s 31-year history. And it’s easy to see why: For $2199, a simple download at one of Dinan’s 129 U.S. dealers immediately endows a 335i with as much as 384 horsepower and 421 pound-feet of torque (versus 300 and 300, respectively). Dinan notes that this is actually more like a 60-hp gain, as BMW’s twin-turbo inline-six comfortably makes more than the advertised 300 horsepower in stock form.

The car tested here goes a little further. Outfitted in “Stage 3” trim, the S3 335i has an oil cooler that is twice as large as standard, a bigger intercooler, a better-breathing carbon-fiber intake, and a freer-flowing exhaust that allows for 1 additional psi of boost versus the 384-hp setup (14 psi total versus 8.8 psi stock). The result is 408 horsepower and a bombastic 440 pound-feet of torque. But it doesn’t come cheap: The aforementioned mods total $8895.

Not surprisingly, throttle tip-in is jumpy as the newfound torque introduces itself. The engine is crazy responsive from 3000 rpm but starts to run out of steam between 6000 rpm and the 7000-rpm redline—the boost tapers off in order to keep the turbos comfortably below their 230,000-rpm limit. And for a turbocharged engine, it still sounds remarkably raspy. At 4.4 seconds to 60 mph and 13.0 through the quarter-mile, the S3 335i is about a half-second quicker than a stock 335i in both regards and nearly matches the last manual M3 we tested.

But even more impressive than the engine work is Dinan’s $4225 chassis overhaul, which includes stiffer springs that lower the 3 by half an inch, adjustable Koni struts and shocks with Dinan-specific valving, front and rear anti-roll bars that mimic the M3’s, front camber plates, a carbon-fiber front strut-tower brace, and new bushings. Also add $5399 for 19-inch forged wheels—they weigh just 20 pounds apiece—plus Michelin Pilot Sport PS2s (265/30 front, 275/30 rear).

These mods make turn-in substantially more eager, and those front tires—40 millimeters wider—effectively squelch understeer. Hold on for 0.99 g on the skidpad—that’s superior to any M3 we’ve tested—and be ready to countersteer when the rear end comes around, jauntily.

Part of what makes the whole thing so exceptional is that, despite the dramatically increased performance, almost nothing is sacrificed except for a ride that’s more brittle and too harsh for our Michigan roads. But the steering is still linear, and nothing has been lost in the way that forces build up; there’s zero nervousness, dartiness, or tramlining; and, astonishingly, the tuned car even weighs 66 pounds less than our last stock 335i. Plus, the S3 335i meets 50-state emissions regs, and Dinan matches BMW’s four-year/50,000-mile warranty. In fact, we couldn’t help but think that Dinan’s chassis tune is probably closer to the BMW ideal. And that’s saying something.

BMW, Dinan S3-R BMW M3

BMW, Dinan S3-R BMW M3
Back in the 1970s, a collegian named Steve Dinan kissed off an engineering career to bust his knuckles pumping up BMWs. One of  his turbocharged Ultimate Driving Machines first laid a patch on these pages in 1988, and since then, we’ve tested eight Dinan BMWs, more or less melting for them all.


The S3-R M3 is emblematic of the type of audacious tinkering we expect from Dinan Engineering’s workshop in Morgan Hill, California—and the kind of prices. Order everything from Dinan, including the engine, suspension, brakes, wheels, fries and a Coke, and the bill comes to $47,836. That is, after you’ve purchased a $60,575 BMW M3 coupe and $1806 in new tires.

Yes, it’s just a wee bit spendy, but this is no casual slap-on of carbon-fiber flounces and plastic galloons. (Dinan offers at least four variations on this theme, from the highly souped-up S3-R to the cosmetic-only S.) The M3’s stock 4.0-liter V-8—a Valjoux 25-jewel chronograph among car engines—is yanked right out, its major organs eviscerated. This, ahem, voids BMW’s warranty, but Dinan takes over and ensures its work for the same four years or 50,000 miles. Dinan, which also builds BMW’s Daytona Prototype racing engines, then repacks the block with a billet crank, forged pistons, and lighter connecting rods. In the event, the bore widens by two millimeters, to 94, and the stroke lengthens by 7.8 mm, to 83.

Thus, in the $31,234 engine portion of the S3-R makeover, Dinan adds 609 cc of displacement, rechambering the engine into the car as a 4.6-liter. Dinan also bores out the throttle bodies (for greater airflow) and fits a smaller, lightweight crank pulley to lessen parasitic power loss from the water pump, the A/C compressor, and the alternator.

Finally, for this particular car, Dinan bolts on a larger, low-restriction air intake and replaces the exhaust midsection with the company’s own stainless-steel “racing” exhaust (i.e., no catalytic converters), which spits thunderclaps and lightning.

With all the internal changes and external tchotchkes, the power subsequently mushrooms, especially in the middle. The S3-R M3 peaks at 527 horsepower at 7800 rpm, Dinan claims, up 113 and down 500 rpm from stock. Perhaps more significantly, the stock torque figure of 295 pound-feet rises by 112, to 407, though the torque peak also rises, from 3900 rpm to 5200.

With tuner cars, the question always comes down to numbers. Dinan’s power figures are predicated on 93-octane gas, which is nearly unobtainable in 91-only California, where we gave the S3-R M3 its test-track licking. Even so, it should have enough extra power to chisel time off the stock M3’s ETs.

Well, the results proved complicated.

Dinan figured we’d turn a quarter-mile in the low-12-second range, rather than the 12.5 seconds we in fact posted, at 118 mph. The many stock, manual-transmission M3s we’ve tested have been only slightly slower (12.6 to 12.9 seconds).

Doing the pathology on the numbers, we realized that the S3-R M3 cost itself time at the line, spinning its tires. Power is nothing without traction, and the car seems to ride atop its own permanent ice cap. On dusty desert pavement, it easily breaks loose its fat Michelins in first and second gears, so it’s no easy car to get out of the hole.

We were slower to 30 mph than in most other M3s we’ve tested, but then the S3-R M3’s power showed, reeling in the stockers and passing them by 60 mph. The tuned car hit 60 in 4.2 seconds, about two-tenths quicker than most of the stock M3s we’ve tested. A better test surface would certainly make for a better launch, and the Dinan M3 would be quicker at the key marks, no question.

With catalytic converters? Dinan says that would cut 23 horses, but running on 93 octane would add 15, so it shouldn’t make much of a difference

Dinan S2-M3

Dinan S2-M3

Why would anyone acquire a car that already had been thoroughly modified by one of the best performance-car companies in the world and then modify it again? That's the question we asked Steve Dinan, the well-known American tuner, when he came by our sweatshop and dropped off his latest car, a modified BMW M3 he's dubbed the S2-M3.

Simple, says he: "Folks who want to go fast start with the fastest car they can get and then come to me to make it go even faster." For BMW fans, the quickest model is the $48,195 333-hp M3, a legendary car that's always on our 10Best list. It's so good that in 1997 we named it the Best-Handling Car, period—money no object.

It's hard to imagine anyone even trying to improve on the M3, but Dinan says his $17,798 package of engine and suspension mods does indeed do just that. This is not a new experience for us. We had the same doubts last year when he dropped off a reworked M5, but sure enough, we did like it better than the stock car.

Dinan acknowledges the inherent dangers of such ventures and is well aware that in stock trim the M3's 333-hp, 3.2-liter six-cylinder engine, for example, is already highly tuned, and there aren't a lot of inexpensive things he can do to significantly increase horsepower. That's why the list of new power parts has just three items on it: an airbox, an airflow meter, and a muffler.

The airbox is larger than the stock unit and also has a snorkel that inhales cold air from the area between the top of the front grille and the hood. In addition to the less restrictive airflow meter, the package includes the relocation of the intake-air-temperature sensor so it's closer to the six throttle bodies, a move Dinan says provides the engine computer with more accurate intake-air-temperature readings. The throttle bodies are also bored out for further airflow increases.

The only change to the exhaust system is the muffler. The standard M3 uses a muffler that has two outlets, so from the rear of the car there are two pairs of exhaust pipes sticking out. Dinan's muffler uses only one larger, smoother outlet because he says more air is able to flow out. A dummy pair of exhaust tips retains the stock look.

Finally, Dinan reprograms the M3's engine computer, which controls a great many engine functions, including the intake- and exhaust-valve timing, spark timing, fuel flow, and throttles. In addition to adapting those engine parameters to the new parts, Dinan increased the rev limit by 200 rpm to 8200 and also removed the top-speed governor. We don't top-speed-test modified cars, but Dinan says the S2-M3 is good for 189 mph.

All the modifications added a claimed 28 horses to the power bank, an 8.4-percent improvement. That's not enough for a customer to sense a thrilling boost in power, so as part of the package, Dinan also puts in a shorter final-drive ratio (3.91:1 versus 3.62:1) to make for sprightlier sprints. It is also interesting to note that thanks to the higher rev limit Dinan's car clears 60 mph in second gear, the same as the stock car.

Dinan feels the greatest improvement he's made over the stock M3 is in the suspension department. As we do, he thinks the M3 is too stiff, but he goes even further, contending that the handling benefits don't justify that hard ride. So the S2-M3 package includes new 12-position adjustable shocks and anti-roll bars, stiffer springs, front camber plates, front and rear strut-tower braces, and larger wheels and tires. Dinan claims his car rides about as well—or not—as the stocker but has a lot more grip. Its 0.96-g skidpad figure is a bunch more than a stock M3's. We've tested three stockers, and the numbers have ranged from 0.84 to 0.87.

We did not see that much of an improvement during the acceleration tests. The S2-M3 zips to 60 mph in only 4.6 seconds, but we've tested a stocker that hit 60 in 4.5. Similarly, the S2-M3 cleared the quarter in 13.2 seconds at 107 mph, and that quick stocker did it in 13.1 at 107. It's worth noting that we've also tested an M3 that needed 4.8 seconds to reach 60 mph and 13.6 seconds to hit the quarter at 105 mph.

Dinan did, however, improve the handling. There's a crispness in the S2-M3 that adds a wonderful liveliness to the driving experience. It's sort of a strange thing, because if you drive an M3, you think it handles pretty well and there aren't really any faults. But then you drive the Dinan car, and it's as if someone had turned on the lights.

Especially noticeable was the turn-in response. The S2-M3 rips through turns with an easy controllability and seemingly limitless grip. We didn't tinker with the adjustable shocks (ours were set with the front slightly stiffer than the rear), but Dinan says there's a large range of adjustability that allows owners to fine-tune the handling for precisely the balance desired. The Dinan car isn't necessarily faster at the drag strip, but on a racetrack, where the extra grip and handling would come into play, it would leave the stocker for dead.

If you don't have the cash for the entire S2-M3 package, all the parts—which are covered by a warranty that matches BMW's new-car one—are available à la carte at one of the 120 BMW dealers that carry and install Dinan parts.

Dinan ISR 3-BMW M Roadster

Dinan ISR 3-BMW M Roadster

You've probably noticed by now that the latest BMW M3 has arrived here with a more powerful engine that used to be exclusive to the European market. What you might not know is that the new engine will also power the 2001 M roadster and M coupe models. That pretty much renders your older M coupe or roadster obsolete, doesn't it?

Unless, that is, you ordered your car to be modified and supplied by Dinan as a factory-works vehicle -- a program Dinan runs in conjunction with BMW of North America through 76 authorized dealers to supply super-quick variants with fully supported warranties.

In the case of M roadsters and coupes, the breathed-on models are available in three stages of tune. S1 and S2 packages include suspension tweaks, engine software upgrades, and induction and exhaust modifications, along with a Dinan plaque and badging. The Stage 2 kit, predictably, goes further with the upgrades and adds big wheels.

But for the seriously horsepower-hungry owner (no need to raise your hand), there's the Dinan ISR 3. That's shorthand for intercooled, supercharged roadster, 3-series, which provides 396 horsepower at 6500 rpm and a stump-tugging 326 pound-feet of torque at 5500.

Sure, the Dodge Viper does even better than that, but this is a 13-foot-long street luge with a 3.2-liter engine. Having close to 400 horsepower in this car would feel almost indecent if it weren't so much fun. There will be only 50 of these ISR 3s produced, so consider yourself fortunate if you ever get to drive one. And consider yourself extremely well heeled if you buy one, because the premium for this little rocketship is $37,000. Yeah, that's on top of the $43,270 base price of an M roadster, ratcheting your out-of-pocket expenses to a whopping $80,270.

For that you get a belt-driven Vortech supercharger delivering 10 pounds of boost to the engine via an air-to-air intercooler that is fitted in the front of the engine bay, where it shares the wind blast produced by the radiator fan. The fan comes on automatically when the engine senses boost and stays on for three minutes to reduce heat soak.

Two differently sized compressor bypass valves are fitted, one ahead and one aft of the intercooler, to eliminate surging or stumbling. The engine also wears an oil cooler; large-diameter, high-flow throttle-body and airflow-meter assemblies; and a high-flow fuel-delivery system to provide sufficient fuel for the increased airflow. A polished and ported intake manifold with increased runner diameters conducts the high-pressure air to the cylinders, while a free-flow stainless-steel exhaust system eases the gas out to the accompaniment of a fine baritone sound.

Both the engine-control computer and the VANOS variable-valve-timing system were reprogrammed to match the engine's new power characteristics. To get all this newfound grunt to the road, Dinan fitted a lightweight clutch assembly that is nearly 15 pounds lighter than BMW's dual-mass unit yet has a 20-percent-greater clamping force. Then, because the car wears big 285/40ZR-17 tires on the rear axle, Dinan replaced the stock 3.23:1 rear end with a limited-slip 3.38:1 differential.

That took care of the motivating aspects of the ISR 3, in itself not an easy or quick exercise, but Steve Dinan soon found that the stock chassis would not handle the power increases safely without substantial revision. The Z3 family, you might remember, took the semi-trailing-arm rear suspension from earlier BMW models. Dinan found the rear end prone to rapid camber and toe-angle shifts during pitch and roll that produced spooky handling.

Chassis flex added its own weird inputs, so Dinan bolted in a strut-tower brace as well as a set of matched performance springs, specially valved Dinan/Koni shocks, anti-roll bars, and camber-control devices. The result is a car that pulled 0.91 g in our skidpad test (Dinan says he has seen 0.92 g) and drove with a surprising combination of comfort and precision.

The ISR 3 now feels secure and planted in bends, with limited sensitivity to throttle position. Body-motion control, it has to be said, is tight, but the car responds in a more linear fashion than its stock siblings, and even the big 255/40ZR-17 front tires haven't markedly increased the front end's sensitivity to pavement grooves. Continued.

Dinan S2-M5

Dinan S2-M5

Here's a shocker: We don't know a single automotive tuner who spends his leisure time under a shady tree reading William Shakespeare. So it's a good bet that tuner Steve Dinan will be reading the following warning from King Lear for the first time: "Striving to better, oft we mar what's well."

Not a problem, apparently, because with Dinan's latest work of art, he has not only fixed a car that wasn't broken but also sought to perfect a car that everyone considers to be as close to perfection as is humanly possible: the BMW M5. Then he casually sent the result to us for review. He didn't even chaperone the thing - he simply dropped it off and told us to keep it as long as we needed.

Conversation around the Lake Erie Spring Water cooler here at Hogback Road was skeptical. Dinan told us that his S2-M5 package - it costs $35,848 - upped the M5's horsepower from 394 to 470 and torque from 368 to 419 pound-feet, and did so without resorting to a turbo or supercharger. A 76-hp gain on a naturally aspirated engine would be an impressive feat on an unstressed, undeveloped engine, but the M5's mill is anything but unstressed.

The M5 V-8 is one of the most impressive motors ever built for the street. It is packed with four cams with infinitely variable valve timing, 32 valves, an aluminum block, eight electronically controlled throttle bodies - one for each cylinder - and an 11.0:1 compression ratio, and it's assembled with a care that results in 394 horsepower from 4.9 liters. It freely revs to 7000 rpm and never feels flat-footed, no matter how low the rev counter.

BMW coupled the engine to a six-speed manual transmission and a buttoned-down, lively chassis. We've never met an M5 we didn't love. It's won every comparison test it's been entered in, and if its $73,624 base price could be trimmed to get below our mid-$60,000 threshold for the 10Best Cars competition, it'd be a shoe-in for an award.

So we figured anyone trying to outdo BMW's engineers would, well, screw up. Maybe the result would be faster, but the M5's overall package could well be spoiled in the quest for more speed.

Dinan approached the task differently when he started on the M5 project two years ago. First, he set out to increase the engine's breathing characteristics. He ditched the stock airboxes and airflow meters for larger, better-flowing units and installed shorter, larger-diameter velocity stacks. Next he bored out each of the throttle bodies.

On the exhaust side, he installed a set of Dinan-made headers that resemble a pile of cooked spaghetti but flow well enough to create another 28 horsepower. In addition, he added a new exhaust system that sounds slightly raspier and weighs 29 pounds less than the stock system. Finally, Dinan lightened the flywheel by seven pounds.

These hardware changes are only a small part of the engine modifications. The real challenge was to reprogram the engine computer to take full advantage of the improved breathing. The M5's computer controls a myriad of engine functions, including the throttles, the timing of all four camshafts, and the usual bits such as the pulse-width and timing of the fuel injection. Each of these functions relies on the other, so change one - timing, for example - and then you likely also have to change everything else.

Writing the optimal program was a long, arduous, and iterative process that Dinan says took the bulk of the two years his company spent developing this package. But hard work paid off with the added 76 horses at peak power and a fatter torque curve that offers more torque at every rpm.

Coupled to the more powerful engine is a shorter final drive (3.45:1 versus 2.81:1). There are also slightly stiffer springs and shocks, special forged aluminum wheels, wider tires, and cooling ducts that direct air to the stock front brakes.

We found the benefits of these changes after our first run on the test track. Dinan's car is a rocket. It rips to 60 mph in 4.1 seconds, to 100 in 10 seconds flat, and through the quarter-mile in 12.7 seconds at 113 mph. The last M5 we tested needed 4.7 seconds to reach 60 mph and turned the quarter in 13.2 seconds at 109 mph. The S2-M5's top-gear acceleration from 50 to 70 mph improved 0.2 second, to 6.2. Dinan says that in addition to raising the stock 7000-rpm rev limit to 7300 rpm, he also removed the 156-mph top-speed governor. We didn't test for top speed, but Dinan suggests the S2-M5 can reach redline in sixth gear, which would be a hair-raising 191 mph. Skidpad grip climbed from the stocker's 0.83 g figure to 0.87.

And we did not find a downside, or any quirky behavior, with the increased performance. The exhaust system delightfully burbles at idle and emits a satisfying rasp at full throttle, but it settles into a subdued hum when cruising. The engine's throttle response is big-block instant. Thanks to the wide gear spacing of the M5's transmission, the shorter final drive does not make for frenzied highway cruising. At 80 mph in sixth gear, the engine revs at about 3000 rpm. Similarly, the suspension changes didn't ruin the M5's balance. Although we didn't have a stock M5 around for direct comparison, Dinan's S2-M5 had the same impressive combination of resilient ride and well-controlled body motions, but with even more grip.

It's a thoughtfully engineered package that feels as though it could have come from the factory. There are even side benefits we didn't expect, such as easier clutch engagement. We never realized how tricky it is to get a stock M5 rolling smoothly until we got in the Dinan car. Dinan says the lightened flywheel gets the credit.

Should you too have to fear of Shakespeare's warning, you may have the S2-M5 system installed on your M5 at any one of the 100 Dinan-licensed BMW dealers. Dinan will match the remainder of BMW's four-year/50,000-mile warranty and will also match that warranty if the package is installed on a new car.

Dinan also offers systems for the BMW 540i that include a supercharger. We haven't had a chance to try out that one yet, but for sure we won't be second-guessing it.

BMW M5

BMW M5
Here is a nearly undisguised prototype of the next BMW M5, which was caught testing at the Nürburgring race track in Germany. Due out in fall 2004, the new M5 will be powered by a V-10—displacing 5.0 or 5.5 liters—that is rumoured to deliver in the neighborhood of 500 horsepower. Transmission choices will likely include a standard six-speed manual and BMW's Sequential Manual Gearbox (SMG).

2012 Toyota Prius v Hybrid

2012 Toyota Prius v Hybrid

Toyota took the wraps off its long-awaited second Prius model, the upcoming Prius v (for “versatility”) at the 2011 Detroit auto show. Scheduled to go on sale this summer as a 2012 model, this most practical of Priuses is measurably larger than the familiar hatchback—the v is 6.1 inches longer, 1.2 inches wider, 3.3 inches taller, and rides on a wheelbase stretched by 3.1 inches. Still, in spite of the larger frontal area and longer roof, the Prius v’s coefficient of drag is claimed to be a low 0.29. And despite sharing no body panels with the hatchback, no one will mistake it for anything but a Prius.

So what effect did the dimensional stretching have? Mostly in gained cargo and rear-seat leg- and headroom. It seats five, not the seven many predicted, but the wagon body swells cargo room to a considerable 34 cubic feet behind the rear seats. Seats fold 60/40 for even more space, and if that’s not enough, the front passenger seat folds flat, too. Rear seats slide fore and aft, and offer a 45-degree recline function, the better with which to enjoy the available panoramic sunroof, which is made from resin. Using the material, Toyota says, offers a 40 percent reduction in weight compared to glass, as well as excellent heat management.

The Prius v whirs along using the same 134-hp hybrid powertrain as the Prius hatchback. Thanks to more mass and different aerodynamics, however, the Prius v is expected to achieve EPA ratings of 42 mpg city, 38 mpg highway, and 40 mpg combined versus 51/48/50 for the Prius hatch. We also expect it to be commensurately slower than the hatch, which is the very definition of unswift—we clocked a 2010 model at 10.0 seconds to 60 for a comparison test.

Pricing has yet to be formally established, but Toyota executives said that we should expect a slight premium over the hatchback.

As we have reported before, the Prius line will not stop with the v. Within a year, two more Priuses—the plug-in Prius and the cheaper, smaller Prius c—will be whirring onto the scene, with another eight hybrid models joining the worldwide Toyota product family in years to come. Whether the additional gas-electrics will be more Prius variants isn’t yet clear, but one thing’s for sure: eco-hippies will have a lot more choices.